First of all, the raw materials of their sauce are very cheap when they are bought. Because the business of big stores is very hot, their demand is great. It will lead to their large purchase volume, and wholesalers will give them low purchase prices, so their costs are very low. And everyone can't eat much sauce bone, and the profit is still considerable.
Second, people who eat big bone buffet sauce don't necessarily only eat big bones. Their shop also has all kinds of hot boiled vegetables and other snacks. Therefore, if such snacks are eaten with sauce bone, it is easy to make people feel full and can't eat a few sauce bones. Moreover, hot dishes and snacks are particularly cheap, so you will be full after eating this, and you won't eat too many bones.
To sum up, although the price of big bones is very expensive, the merchants have a large quantity of goods, and diners will also eat other hot dishes and snacks, resulting in consumers not eating many big bones. Therefore, the price of these self-help sauce bones of 29 yuan is not very expensive, but if you want to get this money back, you must eat more sauce bones.